Lignocellulose is the most abundant renewable biomass on the earth. Enzymatic hydrolysis of cellulosic polysaccharide is key step of lignocellulose biorefineries. To enhance efficiency of cellulose hydrolysis

pretreatment is necessary for effectively breaking its recalcitrant structure.  So

great attentions have been paid for design of pretreatment technologies to crack recalcitrant characteristics of lignocellulose. In this paper

the latest research progresses on lignocellulose pretreatment and recalcitrant characteristics were reviewed

focusing on the new pretreatment technologies and their main advantages

including combined pretreatment

cold pretreatment

green solvents pretreatment and electrochemical approach. Otherwise

the influence of recalcitrant characteristics

such as lignin

crystallinity

accessibility

on cellulose hydrolysis was discussed. The new methods used for analysis of recalcitrant characteristics and the new insight obtained are highlighted in this review. These are useful for evaluation of pretreatment technologies

and identification of key factors that limit cellulose hydrolysis

and can also be a basis for design and screen of appropriate pretreatment technologies

as well as for understand of lignocellulose hydrolysis mechanism.